Background: Psychotic disorders differ in their impact on psychosocial functioning. However, few studies have directly compared psychosocial functioning and its determinants between schizophrenia, schizoaffective disorder (SAD), bipolar disorder (BD), and major depressive disorder with psychotic features (psychotic MDD). Objective: We compared rates of independent living, employment, marriage, and having children between these diagnostic groups in a large national sample of participants with psychotic disorders in Finland. Methods: A cross-sectional substudy of participants (N = 9148) aged 18 to 65 years in the Finnish SUPER study, recruited nationwide from health- and social care settings and with advertisements. Psychosis diagnoses, age of onset, and hospitalizations were collected from healthcare registers. Participants were interviewed for psychosocial functioning. Associations of age of onset, hospitalizations, gender, and education with psychosocial functioning were analyzed using logistic regression models. Results: Of participants, 13.8% were employed or studying, 72.0% living independently and 32.5% had children. Overall, BD was associated with best, SAD and psychotic MDD with intermediate, and schizophrenia with worst level of psychosocial functioning. Greatest differences were found in independent living (OR 4.06 for BD vs. schizophrenia). In multivariate models, gender and number of hospitalizations predicted employment, marriage, and independent living in all diagnostic categories, and age of onset in some diagnostic categories. Conclusions: Level of functioning and psychosocial outcomes differed markedly between psychotic disorders, particularly in independent living. Outcomes were worst for schizophrenia and best for BD. Across all psychotic disorders, female gender and lifetime number of hospitalizations had strong independent associations with marriage, employment, and independent living.